Anderson Michael C, Dharmasri Poorna A, Damenti Martina, Metzbower Sarah R, Laghaei Rozita, Blanpied Thomas A, Levy Aaron D
Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA.
Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Nat Commun. 2025 Aug 12;16(1):7460. doi: 10.1038/s41467-025-62766-y.
Tight coordination of spatial relationships between protein complexes is required for cellular function. In neuronal synapses, proteins responsible for neurotransmission form subsynaptic nanoclusters whose trans-cellular alignment modulates synaptic signal propagation. However, the spatial relationships between these proteins and NMDA receptors (NMDARs), which are required for learning and memory, remain undefined. Here, we mapped key NMDAR subunits relative to active zone and post-synaptic density reference proteins using multiplexed super-resolution DNA-PAINT microscopy in rat hippocampal neurons. GluN2A and GluN2B subunits formed diverse nanoclusters that, surprisingly, were not localized near presynaptic vesicle release sites marked by Munc13-1. However, a subset of release sites was enriched with NMDARs, and modeling indicated this nanotopography promotes NMDAR activation. These enriched sites were internally denser with Munc13-1, aligned with PSD-95, and closely associated with specific NMDAR nanodomains. NMDAR activation rapidly reorganized this relationship, suggesting a structural mechanism for tuning NMDAR-mediated synaptic transmission. These findings suggest synaptic functional architecture depends on assembly of and trans-cellular spatial relationships between multiprotein nanodomains.
细胞功能需要蛋白质复合物之间空间关系的紧密协调。在神经元突触中，负责神经传递的蛋白质形成亚突触纳米簇，其跨细胞排列调节突触信号传播。然而，这些蛋白质与学习和记忆所需的NMDA受体（NMDARs）之间的空间关系仍不明确。在这里，我们使用多重超分辨率DNA-PAINT显微镜在大鼠海马神经元中绘制了相对于活性区和突触后密度参考蛋白的关键NMDAR亚基。GluN2A和GluN2B亚基形成了不同的纳米簇，令人惊讶的是，它们并不位于由Munc13-1标记的突触前囊泡释放位点附近。然而，一部分释放位点富含NMDARs，建模表明这种纳米拓扑结构促进NMDAR激活。这些富集位点在内部与Munc13-1结合更紧密，与PSD-95对齐，并与特定的NMDAR纳米域密切相关。NMDAR激活迅速重组了这种关系，提示了一种调节NMDAR介导的突触传递的结构机制。这些发现表明突触功能结构取决于多蛋白纳米域的组装及其跨细胞空间关系。
